Hot-air furnace.



W. P. HARTFORD.

HOT AIR FURNACE.

(Application filed Mar. 11, 1901.-) (No Model.) 3 Shsets-$heet l.

No. 689,078. Patented Dec. l7, I901.

19i l'ueoam 11-1: noRms PUERS co, pumbumu. wxsnmorou. n. c.

No. 689,078. Patented Dec. I7, I901.

.W. P. HARTFORD.

HOT AIR FURNACE.

(A lication filed Mar. 11. 1901. (No Model.) 3 Sheets-Sheet 2.

anpzwtoz No. 689,078. Patented Dec. I7, 1901.

, w. P. HARTFORD.

HOT AIR FURNACE.

(Application filed. Mar. 11, 1901.)

3 Sheets-Sheet 3.

(No Model.)

awuemtoz THE Ncmms vzr'zas co, Pam-ammo WASHINGTON a c.

UNITED STATES PATE T @FFlCF.

WILLIAM PRESTON HARTFORD, OF CASSVILLE, W'ISCONSfN, ASSIGNOR OF TWO-THIRDS TO FRANK G. HORNBOGEN AND EDVIN SMEDLEY,

HOT-AIR FU RNACE.

SPECIFICATION forming part of Letters Patent No. 689,078, dated December 17, 1901.

Application filed March 11, 1901. Serial No. 60,560. (No model.)

To all whom. it may concern:

Be it known that I, WILLIAM Pansron HARTFORD, physician, a citizen of the United States, residing at Cassville, in the county of Grant and State of Wisconsin, have invented certain new and usefullmprovements in Hot.- Air Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which .it appertains to make and usethe same.

My invention relates to a special construction of a hot-air heater or furnace and of its auxiliary devices. The action of the draft of ordinary chimneys varies according to their size, height, and location and according to the velocity or direction of the wind, and this varying action of the wind will increase or decrease the draft, thus requiring constant attention to change the dampers or to be changing frequently the direct draft and the indirect or check draft in order to prevent unnecessary consumption of fuel and to strive to keep the rooms at an even or desired temperature. My invention does away entirely with this necessity of constant attendance, because my check-draf t device hereinafter described acts automatically with every variation in the action of the chimneydraft, as will presently be described.

In the accompanying drawings, Figure 1 is a longitudinal section through the brickcased combustionchamber, drum, checkdraft, hot-air pipes, and by-pass. Fig. 2 is a longitudinal section through the brickwork, showing the furnace and drum in position or not in section. Fig. 3 is a front elevation of a furnace bricked in. Fig. 1 is a foundation plan of the furnace bricked in. Fig. 5 is a foundation plan of a furnace that is cased in with corrugated iron or steel sheets instead of with brickwork. Fig. 6 is a transverse section through a furnace cased in with corrugated-iron sheets. Fig. 7 is a frontel evation of furnace cased with corrugated-iron sheets.

Observe that the arrows (not feathered) indicate the direction of the heat and gases generated in the furnace, while the arrows having feathers thereon indicate the source and direction of the fresh air passing around the furnace and around the superheating-drum on its way to the rooms of the building.

A is the combustion-chamber of the furnace, made of boiler-iron or steel that will not crack, as do cast-iron furnaces.

B is the superheating-drum, made of thin wrought-iron or mild steel.

0 is a rod that binds the drumheads to the drum.

01 (Z d d are eyebolts binding the furnace to the heads.

E is a by-pass cast in the head, as shown, and thereby doing away with the ordinary breeching. It spans an outlet at the inner end of the furnace A and also an inlet at the same end of the drum B, and thus passes the products of combustion from the furnace to the drum.

fffff are the hot-air pipes, leading to the rooms to be heated.

g g are the fresh-air pipes, leading in from outdoors or can be arranged to take air from a cellar. As shown, this cold air for circulating is entered directly under the fire-chamber and just where the heat is the greatest. This provision protects the furnace from being burned out at this point.

h is an inlet air-door beneath the chamber Ato be used to admitcool airin warm weather. As indicated by the feathered arrows, the route of cool air from h rises up outside the cylinders and also is free to pass up at the ends and around the by-pass and thence to the pipes fff, the.

K is a direct-draft door located in the main door a, which door, as shown, covers the entire mouth of the furnace A to admit the largest logs. This door has a chain leading to an office or elsewhere for convenience. All

the ashes are readily removable from this month of A upon simply swinging open the main door to. None can enter into the hotair pipes nor into the rooms nor below the furnace.

L is an automatic check-draft on the drum B and having an adjustable counterbalance weight and lever m, that can be set to suit the side, height, or location of any chimney and according to the velocity or direction of the wind and that will automatically open when the direct draft K is closed, as the action of the draft from the final outlet to the chimney will then be on the check-draft door L, which, being nearly balanced, acts promptly, and when the direct draft K is opened again the action of the chimney being supplied again from the direct draft K the counterbalance m closes the door of the checkdra ft L.

N N are corrugated side sheets of a furnace. The object in using this typeof sheet is that they will permit the cylinderand drum to expand and contract in heating and cooling, the shape of the sheets allowing them to come and go like a leather bellows.

O O O O 0 (see Figs. 1 and 2) are the top hotair-pipe plates, arranged with lapped joints to prevent the escape of heat.

P is the final outlet to the chimney.

For convenience in cleaning the drum B the check-draft box is swung upon a pivot Q and look (see Fig. 3) with an open jaw on collar-bolt R, which enables the operator to swing it aside for cleaning, when it again drops into position from its own gravity.

From the above description it will now be seen that when fire is made in the furnace A, thus heating the furnace and the superheating-drum B, the hot air rushes to the top of the air-roon1 sin-rounding the furnace and drum through the hot-air pipes ff f, 850. The vacuum thus created is filled by an influx of fresh air from any point desired, as indicated by pipes g g and by dotted lines, (see Fig. 4,) leadingin from any desired place, and that when the rooms are sufficiently heated the direct draft K being closed the checkdraft L automatically opens"; as stated above, thus preventing the formation of creosote, which in ordinary constructions runs down from the chimney into the furnace or stove, doing much damage, the check-draft L in my construction admitting enough fresh air to prevent this nuisance as well as saving fuel. The by-pass E in the back plates displaces the breeching between two cylinders, which is always a weak and expensive feature. The combustion-chamber A has no bottom opening or grate nor any ash-box and is made large and long enough to burn the longest cord-wood sticks without cutting. Both furnace and drum are made of wrought-iron or mild steel which will not crack, warp, or break. The corrugated side sheets are of a character that will admit of expansion and contraction of furnace and drum without sustaining injury therefrom.

The entire apparatus is light, strong, and durable, and it is economicalin the use of fuel and can be made for one-third the usual cost of any other furnace known to me, bringing it within the reach of all, the entire cost being less than a goodstove.

Having thus described my invention, I claim I A hot-air furnace adapted for burning uncut cord-wood, a combustion-cylinder and a superheating-cylinder both inc-losed within a special furnace-wall composed of metal plates at front and rear as shown broader than the cylinders, and of side sheets of corrugated metal secured to the ends of said plates, these sheets being thereby offset from the cylinders to leave open space between them and such sheets, all as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM PRESTON HARTFORD. Witnesses:

D. W. CLARK, LILLIS CLARK. 

